It is known that the use of soliton pulses in optical fiber communication systems potentially makes possible systems having exceedingly high information transmission capacity. See, for instance, U.S. Pat. No. 4,406,516, incorporated herein by reference. It is also known that soliton pulses can be compatible with non-electronic amplification, e.g., amplification by means of optical amplifiers such as Raman effect fiber amplifiers or rare earth (e.g., erbium)-doped fiber amplifiers, but not excluding such amplifiers as non-electronic semiconductor amplifiers. See, for instance, U.S. Pat. No. 4,558,921, also incorporated herein by reference.
It has recently become apparent that prior art soliton communication systems using intermediate amplification are not likely to be capable of operation at the projected very high bit rates over large distances, due to significant temporal jitter in the soliton arrival at the receiver end of the system. This jitter is due to, inevitably present, amplifier noise associated with the intermediate amplifiers in the system. This jitter-generating mechanism is frequently referred to as the Gordon-Haus effect. See J. P. Gordon et al., Optics Letters, Vol. 11(10), pp. 665-667. Jitter at the receiver can also be due to temporal or amplitude jitter at the transmitter. By "jitter" is meant a timing error in pulse arrival time. Regardless of the source of the jitter, its existence can severely limit the useful bit rate for long length prior art soliton communication system designs.
A technique for eliminating the jitter is disclosed in M. Nakazawa et al., Electronics Letters, Vol. 27, page 1270. The technique utilizes active electronic components such as modulators and thus is relatively complex and would at best be costly and difficult to implement.
In view of the evident importance of communication systems capable of operation at the highest possible bit rates over large distances it would be highly desirable to have available soliton systems that comprise relatively simple and low cost means for eliminating, or at least substantially reducing, pulse temporal jitter at the receiver. This application discloses such soliton systems.